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高效液相色谱-串联质谱法结合多糖衍生物手性固定相拆分氰戊菊酯 总被引:1,自引:0,他引:1
建立了以多糖衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分氰戊菊酯对映体的方法。在反相液相色谱条件下,考察了手性固定相的种类、流动相组成、柱温、流速对氰戊菊酯4个立体异构体分离的影响。同时,利用热力学方法对氰戊菊酯的立体异构体与固定相之间的色谱保留和分离的热力学机理进行了探讨。结果表明:采用Lux Cellulose-3(纤维素-三(4-甲基苯甲酸酯))手性色谱柱,在以流动相为乙腈-水(5 mmol/L甲酸铵)=(55:45,V:V)流速0.4 mL/min,柱温30℃的条件下,可在14 mins内实现氰戊菊酯4个立体异构体的基线分离。拓展了HPLC-MS/MS在菊酯类手性农药对映体分离及检测上的应用。 相似文献
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合成了萃取拆分氰戊菊酸(FA)对映体的手性选择体L-酒石酸异丁酯.研究了氰戊菊酸对映体在含有手性选择体L-酒石酸异丁酯的水-有机相双相体系中的萃取分配行为.考察了有机稀释剂类型、L-酒石酸异丁酯浓度、pH值和磷酸盐浓度诸因素对分配系数(K)和分离因子(α)的影响.研究结果表明:L-酒石酸异丁酯与S对映体形成的复合物稳定性比与R对映体形成的复合物要好;1,2-二氯乙烷作为有机稀释剂更有利于萃取分离;随着L-酒石酸异丁酯浓度的增大,K逐渐增大,α先增大后减小,当L-酒石酸异丁酯浓度为0.30 mol\5L-1时,α达最大;pH值增大,K和α都降低;磷酸盐浓度对分配系数和分离因子也有较大影响. 相似文献
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建立并优化了高效液相色谱手性固定相分离盐酸克伦特罗对映体的方法。使用两种Pirkle型手性固定相(α-Burke-2和Pirkle-1J)拆分了盐酸克伦特罗对映体,考察了缓冲盐添加剂,有机溶剂种类和浓度,以及柱温对保留行为和分离的影响。当流动相为二氯甲烷-乙醇(19:1,V/V)含5 mmol/L乙酸铵,流速2.0 mL/min,柱温20℃时,盐酸克伦特罗对映体在α-Burke-2色谱柱上能实现较好的分离,分离度可达1.85;在Pirkle-1J色谱柱上,分离度可达0.64。盐酸克伦特罗对映体与Pirkle型固定相之间的π-π主客体相互作用和氢键作用是实现对映体分离的最主要分离机制。方法可用于盐酸克伦特罗对映体的质量控制及立体选择性药代动力学的研究。 相似文献
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采用高效液相色谱在正相条件下对常温稳定存在的19种手性多氯联苯(Polychlorinated biphenyls,PCBs)进行了拆分,对比了5种不同多糖类手性色谱柱的拆分效果.其中Lux Cellulose-1,Cellulose-3和Cellulose-4分离效果较好,在Cellulose-1上PCBs91,136,139,149和171可基线分离,在Cellulose-3上PCBs45,84,88,95,131,135,144和149能够完全分离,在Cellulose-4上PCBs88,131,139,171和174能够完全分离,在以上3种色谱柱上PCBs132,175,176,183,196和197可部分分离,但Cellulose-2和Amylose-2对这19种手性PCBs分离效果很差.考察了温度对拆分的影响,结果在5℃~30℃C之间,PCBs对映体在Cellulose-1和Cellulose-3上对应的范特霍夫方程线性关系较好,而Cellulose-4受柱温影响不稳定.手性PCBs拆分过程整体受焓驱动,温度降低有利于对映体分离.利用在线旋光确定了各PCBs的对映体洗脱顺序,结果表明PCBs对映体的拆分程度和旋光洗脱顺序受苯环上氯原子取代数目和取代位置的影响. 相似文献
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《色谱》2015,(6)
采用高效液相色谱法,以不同配比的正己烷-异丙醇为流动相,在正相色谱条件下,考察了6个3α-酰氧基-6β-乙酰氧基莨菪烷对映体在淀粉型手性固定相Chiralpak AD、纤维素型手性固定相Chiralcel OD-H上的分离情况,以建立该类化合物的手性拆分方法。结果表明,在Chiralpak AD手性柱上,对映体6实现完全分离,而对映体1完全不能分离;在Chiralcel OD-H柱上,对映体1、4、3分别实现完全分离、基线分离和基本分离,对映体6只能实现部分分离;对映体5在两种手性柱上都完全不能被分离。说明固定相手性空腔的结构对化合物的拆分结果影响很大。研究发现,C-3α位取代基团的空间位阻效应主导手性固定相对对映体的选择性识别作用,而化合物与固定相之间的分子间作用力对手性拆分也产生重要影响。研究结果为其他莨菪烷类化合物的手性拆分提供了参考。 相似文献
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将纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)涂敷于氨丙基硅胶上制备成高效液相色谱(HPLC)手性固定相,对手性农药顺式、反式氯氰菊酯和烯唑醇对映异构体在正相条件下进行了手性拆分。分别以正己烷和石油醚为流动相,考察改性剂的含量;在正己烷流动相条件下考察了色谱柱长度、温度对拆分效果的影响。试验结果显示,改性剂含量的减少、长色谱柱及降低温度均有利于对映体的分离。该手性固定相对顺式、反式氯氰菊酯具有非常强的立体选择性,对烯唑醇也有较好的拆分能力。 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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